On Sat, 2016-06-18 at 10:14 -0700, Dennis McClellan wrote:

I get the gray frozen screen, not always, but often. After a few seconds or sometimes minutes a message pops up and states “Ubuntu has a problem and needs to shut this program down.

What happens there is Compiz (the WM for Unity) pings applications every so often with an X message to see if they respond. If the application doesn't return the "everything is okay" message back Compiz desaturates the application's windows to show that it isn't responding. Generally this means that there is a problem with the application, but it could mean that it's just working on something else and not responding to its X11 event stream.

I like the feature, but if you find it annoying you can go into CompizConfig Settings Manager and adjust the "Ping Delay" under "General Options" to be something wildly large and it is unlikely to happen again. Default is 5 seconds.

Ted